Articulated laser beam guide tube

ABSTRACT

An articulated guide tube having a reflector mirror for guiding an input beam such as a laser beam freely in any desired direction without use of any space-taking, heavy-weight carrier. The mirror is rotated by a specially constructed gear mechanism by an angle equal to one-half of an angle by which the beam is to be oriented with respect to the direction of the input beam.

United States Patent Karube et al.

[ 51 Apr. 25, 1972 ARTICULATED LASER BEAM GUIDE TUBE inventors: Norio Karube; Yasuyuki Morita, both of Kadoma, Osaka, Japan Matsushita Electric Industrial Company Limited, Kadoma, Osaka, Japan Filed: Sept. 24, 1969 Appl. No.: 860,647

Assignee:

Foreign Application Priority Data July 28, 1969 Japan A l/60679 Sept. 27, 1968 Japan ..43/7090l U.S. Cl ..350/52, 356/250, 350/288 Int. Cl. ..G02b 23/08 Field ofSearch ..350/52, 70, 285,288;356/250;

[56] References Cited UNITED STATES PATENTS 1,985,077 l2/i934 Burkhardt ..356/250 3,040,626 6/1962 Grifiioen 350/28 8 3,383,151 5/1968 Kohler et al. ..350/285 3,450,457 6/1969 Clave et al. ..350/7O Primary Examiner-David Schonberg Assistant Examiner-Michael J. Tokar Attorney-McCarthy, Depaoli, OBrien & Price 5 7] ABSTRACT An articulated guide tube having a reflector mirror for guiding an input beam such as a laser beam freely in any desired direction without use of any space-taking, heavy-weight carrier. The mirror is rotated by a specially constructed gear mechanism by an angle equal to one-half of an angle by which the beam is to be oriented with respect to the direction of the input beam.

9 Claims, 14 Drawing Figures PATENTEUAPR 25 I972 3,658,406

INVENTOR NORQO KARUBE BY YASUYUKI MORITA a A 10M 2. (DIM ATTORNEY PATENTEDAPR 25 I972 3 6 58 406 sum 20F 5 INVENTOR NORIQ KARUBE BY YASUYUKI "ORITA WLCw-J WL B'M ATTORN EY PATEMTEDAPMSIQR 3658,4063

SHEET 3 BF 5 INVENTQR NORIO KARUBE BY YASUYUKI MORITA QMMIMLWW ATTORNEY PATENTEDAPR 25 m2 SHEET Q 0F 5 INVENTOR NORIO KARUBE BY YASUYUKI ulonn'A fluM, 10 5;

ATTORNEY PATENT'EDAPMS I972 3. 658,406

SHEET 5 OF 5 INVENTOR NORIO KARUBE BY YASUYUK OR'TA ATTORNEY 1 v ARTICULATED LASER BEAM GUIDE TUBE The present invention relates generally to a laser apparatus and has its particular reference to an articulated tube for guiding and orienting a laser beam in a desired direction.

Although the articulated laser beam guide tube as proposed by this invention finds wide applications where a laser or other unidirectionally advancing beam is to be used, the tube will be herein described, only for illustrative purposes, as being applied to a surgical cutting apparatus using a laser beam as cutting medium. The guide tube as applied for this purpose is assumed to serve as a scalpel" used in the usual surgical operations.

In the surgical operations presently practised such as for severing an affected part from a human skull, an electric drill,

fret saw, chisel and other similar tools have been used despite their inherent drawbacks. Foremost of such drawbacks are the prolonged operation, uncomfortable vibrations transferred to the skull, and taint to the affected part of the skull resulting from the direct contact of the tool with the surrounding human tissues.

In order to overcome these drawbacks, there is proposed a cutting apparatus using a laser beam whereby the affected part is severed without direct mechanical contact therewith and with increased operation efficiency. In the apparatus of this type, it is necessary that the laser tube, from which the laser beam is directed to the affected part of the patient, is placed on a suitable movable carrier to facilitate the operator to manipulate the tube during the operation.

The laser tube thus placed on the carrier is, though mobile on the floor, anyway fixedly mounted on the carrier and it has still a disadvantage in that the precise scanning in a desired path can not be achieved because of the restriction in freely orienting the tip of the tube.

It is therefore an object of this invention to provide an improved laser beam guide tube which can be oriented freely in a desired direction .without use of any space-taking, heavyweight carrier.

It is another object of the invention to provide a laser beam guide tube which can be easily manipulated to provide for increased scanning accuracy required, for instance, for surgical operations.

1 Other and further objects, advantages and features of the invention will be apparent to those skilled in the art from the following description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view showing the general construction of an articulated laser beam guide tube according to the invention as combined with a known laser beam emitting device;

FIG. 2a is an enlarged top plan view of a gear box used in the guide tube of FIG. 1 with its top cover removed;

FIG. 2b is a further enlarged perspective view of the gear box shown in FIG. 2a;

FIG. 2c is a section on line 1-1 of FIGS. 2a and 2b;

FIG. 3a is an enlarged lengthwise section of a stationary tube member of the guide tube shown in FIG. 1;

FIG. 3b is similar to FIG. 3a but shows a modification thereof;

FIG. 4a is a perspective view of a modification of the gear box of FIGS. 2a, 2b and with its enclosure removed;

FIG. 4b is a section on line II-II of FIG. 4a;

FIG. 5 is a perspective view showing the relative positions of leaf springs and coil springs used in the gear box of FIGS. 4a and 4b;

FIG. 6 is a lengthwise section of a moving tube member and a portion of the gear box in operation;

FIGS. 7a and 7b are a top plan view and a perspective view, respectively, of a reflector mirror used in the gear box of FIGS. 4a and 4b;

FIG. 8 is a perspective view of a modified form of the tube arrangement illustrated in FIG. 1; and

FIG. 9 is a lengthwise section of the leading portion of the moving tube member used in the tubes of this invention.

The laser beam guide tube which is generally designated at 10 in FIG. 1, is used in combination with a suitable known laser beam emitting device 11 whatever purposes the tube may be used for. The construction of the device 11 per se is well known in the art and as such the discussion on this device is herein omitted. Suffice, therefore, it to say that the device 11 is so arranged as to generate and supply a laser beam of predetermined coherence in a predetennined direction to the guide tube 10 to which the invention is directed and is placed on a suitable stationary support or base (not shown).

Referring to FIG. 1, the laser beam guide tube 10 largely comprises a stationary tube member 12 connected at one end with the laser beam emitting device 11 and a moving tube member 13 connected at one end through a gear box 14 with the other end of the stationary tube member 12 and opened at the other to the outside. The moving tube member 13 is rotatable relative to the stationary tube member 12 on a given plane through the gear box 14. The stationary and moving tube members 12 and 13, respectively, are positioned in such a manner that the imaginary extensions of the axesof the two tube members meet each other at a fixed point about which the moving tube member 13 rotates. This fixed point is hereinafter referred to as a pivotal point. The gear box 14 has accommodated therein a gear-driven reflector mirror. The reflector mirror, which will be described and shown in detail, is so constructed and arranged as to change the direction of the laser beam passed through the tube member 12 and to guide the beam correctly to the tube member 13. The laser beam supplied unidirectionally from the device '11 is thus oriented and projected from the moving tube member 13 is a desired direction, so that an object, which may actually be an affected part of a patient, can be scanned freely and precisely.

In order to make understood the relative motion of the reflector mirror accommodated in the gear box 14, reference is now made to FIGS. 20, 2b and 2c, which show the interior of the gear box.

As best shown in FIG. 2a, the gear box 14 has a cylindrical enclosure 15. Through the wall of the enclosure 15 is tightly and fixedly inserted the inner end portion of the stationary tube member 12. The enclosure 15 has formed therein a peripherally extending opening 16 through which the moving tube member 13 is inserted rotatably about the aforesaid pivotal point. It may be noted that the two tube members 12 and 13 have their inner ends slightly extending from the inner surface of the enclosure 15 and are positioned on the substantially same plane. A curved shutter 17 is attached to the moving tube member 13. The shutter 17 has substantially the same curvature as that of the enclosure 15 and is held in contact with the inner surface of the enclosure slidably about the central axis or the pivotal point of the gear box 14, whereby the opening 16 is optically shuttered even though the moving tube member 13 is moved therein.

The enclosure 15 has accommodated therein a gear mechanism which is generally represented by 18.

The gear mechanism 18 has a'reflector mirror 19 fixedly fitted in a recess formed in a reflector support 20 which is integrally connected to a pivotal shaft 21. The pivotal shaft 21 is located at the aforesaid pivotal point at which the imaginary extentions of the axes of the two tube members 12 and 13 meet each other, which point preferably corresponds substantially to the center of the enclosure 15. The pivotal shaft 21 is integrally connected with the reflector support 20. The gear mechanism 18 further comprises a spur gear 22 rotatably mounted on the pivotal shaft 21 and fixedly connected to the stationary tube member 12 and a spur gear 23 fixedly mounted on the pivotal shaft 21 at a suitable spacing from the spur gear 22. Spur gears 24 and 25 are rotatably mounted on a stationary shaft 26 provided in parallel to and at a suitable spacing from the pivotal shaft 21. The gears 24 and 25 engage with the spur gears 22 and 23, respectively. According to an important feature of this invention, the ratio of numbers of teeth in the gears 22 and 24 is I vs. 2, while that in the gears 23 and 25 is 1 vs. I. The stationary shaft 26 is anchored at either end thereof to a suitable mount. The mount is herein shown to be a member 27 which is in the form of a tube connected by a pair of supporting plates 28 and 28 to the stationary tube member 12 fixedly. The pivotal shaft 21 is inserted through this tubular member 27. A pair of supporting plates 29 and 29' are pivotally attached to the ends of the shaft 21. These supporting plates 29 and 29' are in line with the extentions of the moving tube member 13. Each of the plates 29 and 29' has its one end connected to the tube member 13 and its other end secured to the spur gear 22.

1f preferred, the shafts 21 and 26 may be secured to the wall of the enclosure of the gear box and, in this instance, the member 27 may be dispensed with. If desired, furthermore, the relative positions of the gears 22 and 23 and accordingly the gears 24 and 25 may be arranged otherwise: the gears 22 to 25 may be all accommodated within the tubular member 27; the gears 22 and 24 may be positioned inboardly of the gears 23 and 25, respectively, with respect to the reflector mirror 19. For an increased performance stability of the gear box, an additional set of gears (not shown) which are similar to the gears 22 to 25 may be provided on the opposite side of the tubular member 27.

In order to describe the operation of the gear box thus constructed, the moving tube member 13 is assumed to happen to be positioned at an angle of to the stationary tube member 12 in its original position. In operation, when the moving tube member 13 is rotated by an angle of A0 either toward or away from the stationary tube member 12, the spur gear 21 complete with the supporting plates 29 and 29' is turned accordingly by the same angle A0. The rotation of the spur gear 22 causes the spur gear 24 to rotate by an angle corresponding to one-half of the angle A6, i.e. by the angle of /&A0 in the opposite direction of the rotation of the gear 21, since the gear ratio of the meshed pair is 1 vs. 2 as is previsouly mentioned. The rotation of the spur gear 24, in turn, causes the spur gear 25 to rotate by the same angle and in the same direction as the gear 24 rotates. As a result, the spur gear 23 which has the same number of teeth as the gear 25 is turned by the angle of zAG in the same direction as the spur gear 22 and accordingly the moving tube member 13 turn complete with the pivoltal shaft 21. This causes the reflector mirror 19 to rotate by the desired angle of lzAO. The incident laser beam is thus correctly reflected by the reflector mirror 19 by the desired angle of 0+A0 or 0-A0 with respect to the direction of incidence and is to be guided to the moving tube member 13. In this instance, however, the angle A6 is limited depending on the specific geometry of the gear box 14, for example, on the diameters of the two tube members 12 and 13 or the circumferential length of the curved shutter 17. Such geometry of the gear box can be determined as desired.

If it is desired to have the gear box 14 rotated about the axis of the stationary tube member 12, the member 12 may be divided into two mating halves 12a and 12b, as illustrated in FIG. 30. As shown, one half 12a has a reduced end while the other half 12b has a bore which is sized in substantial correspondence with the reduced end of the former. The half 12b receives through its bore the reduced end of the half 12a in a peripherally slidable fashion. Between these two halves 12a and 12b are preferably interposed at least two cylindrical ball bearings or other suitable antifriction means 30. Thus, the half 12a or 12b connected to the enclosure is permitted to rotate about the axis of the opposite half 12b or 120, respectively, through the bearings 30, so that the gear box 14 and accordingly the reflector mirror 19 can rotate about the axis of the stationary tube member 12. It may be noted that one of the halves 12a and 12b is fixedly connected with the above-mentioned laser beam emitting device 11 and the other to the enclosure 15 ofthe gear box 14.

Where, furthermore, it is desired to enable the gear box 14 to move in the axial direction of the stationary tube member 12, a cylindrical roller bearing 31 may be interposed between the two halves in lieu of the ball bearings 30, as illustrated in FIG. 3b. Here, the halves as dented by 12c and 12d have claws or stops at their extreme ends whereby the halves 12c and 12d are prevented from being disengaged from each other.

It may be appreciated the gear box 14 can be constructed difierently from the embodiment shown in FIGS. 2a, 2b and 2c without departing from the spirit and scope of this invention. For example, the gear box may be constructed in such a manner as to function as a universal joint as illustrated in FIGS. 40, 4b, 5 and 6, wherein like reference numerals identify like parts or members shown in the preceding figures.

As will be discussed in more detail, the moving tube member 13, in this example, is arranged to be rotatable not only on the plane including the axes of the two tube members but also on the plane normal to the former plane, thereby providing a bidirectional rotation of the moving tube member 13.

Reference will now be made to FIGS. 40 and 4b showing the detailed construction of the gear box 14, which is this time shown to be enclosed by a spherical enclosure 15 having provided therein a pair of parallel flat inner walls 32. The stationary tube member 12 is secured to the enclosure 15 with its leading end terminating at the inner spherical wall of the spherical enclosure 15. To the inner end of the moving tube member 13 is fixedly attached four leaf springs 33a and 33b angled at to each other and is secured to the spherical shutter 17. The curvature of the shutter 17 is substantially the same as that of the spherical enclosure 15. The leaf springs 33a and 33b are connected at their inner ends with a squareshaped, open-ended box 34 in which is accommodated a reflector support 35. A pair of pivotal shafts 21a extend from the box 34 and are pivotally received at their ends by the flat surfaces 32 of the spherical enclosure 15. Between the squareshaped box 34 and the flat surfaces 32 are provided a pair of two spur gears 22a and 23a through which the pivotal shafts 21a extend. The outer gears 23a are secured to the pivotal shafts 21a and the inner gears 22a to the ends of the leaf springs 330, as is seen from FIGS. 40 and 4b. To the flat surfaces 32, furthermore, are integrally anchored a pair of stationary shafts 260 each of which has two spur gears 24a and 250 connected pivotally thereto and formed integrally with each other. These spur gears 22a to 25a are arranged to function similarly to those of the first embodiment. In other words, the spur gears 22a and 23a are held in meshing engagement with the spur gears 24a and 25a, respectively. The gear ratio of the gears 22a and 24a is 1 vs. 2 while the gear ratio of the gears 23a and 25a is 1 vs. I.

A pair of pivotal shafts 21b are, as seen in FIG. 4a, pivotally inserted through the facing walls of the square-shaped box 34 and are fixedly connected to the outer walls of the reflector support 35. The shafts 21b are rectangular to the shafts 21a. There are mounted on the pivotal shafts 21b a pair of two spur gears 22b and 23b. The gears or inner gears 22b are secured to the ends of the leaf springs 33b and are pivotally connected to the shafts 21b. The gears or outer gears 23b, on the other hand, are integral with the pivotal shafts 21b. A pair of stationary shafts 26b mounted parallel to the pivotal shafts 21b are anchored to the square box 34 and have provided pivotally thereon two spur gears 24b and 25b formed integrally with each other. In parallel to the moving tube member 13 and the leaf springs 33a and 33b may be mounted, if desired, four coil springs 36a and 36b acting as dampers, which springs are fixed at their one ends to the moving tube member 13 and at the other ends to the associated leaf springs 33a and 33b, as best seen in FIG. 5 which shows the relative positions of the leaf springs 33a and 33b and the coil springs 36:: and 36b.

When, in operation, the moving tube member 13, which has been positioned at an angle 0 to the stationary tube member 12, is rotated by the angle A6 from its initial position, for example, on a horizontal plane, then the square-shaped box 34 and accordingly the reflector mirror 19 are turned by the angle 6A0 due to the driving motions of the spur gears 22a to 25a and 22b to 25b. Whereas, if the moving tube member 13 is further turned by the angle A0 on a vertical plane, then the square-shaped box 34 and the reflector support 19 are turned by the angle AM). The bidirectional movement of the moving tube member 13 is accomplished in such manner. it may be mentioned that the four leaf springs 33a and 33b are warped inboardly or outboardly when the moving tube member 13 is rotated but are not permitted to warp in their widthwise directions.

The reflector mirror 19 may be mounted on the reflector support 35 in any suitable manner as far as the intent of having the laser beam reflected in a desired direction is maintained. Suffice, however, it to say that the mirror 19 has its reflective surface located on a plane including the pivotal point of the moving tube member 13.

One preferred example of the construction arrangement of the reflector mirror and reflector support is shown in FIGS. 7a and 7b. As shown, the reflector mirror 19 is mounted at a predetermined angle to the axis of the shaft 21b through the reflector support 35. A portion of the wall on that side of the reflector support which is located in the path of the outgoing beam may be preferably removed or notched not to obstruct the advance of the reflected beam, as seen in FIG. 7b.

In order to make it possible to more freely manipulate the articulated guide tube as hereinbefore described, one or more additional gear boxes may be used in combination with the described tube. One example of such modified form of articulated guide tube is illustrated in FIG. 8.

As shown, two additional gear boxes 14' and 14" are provided between the gear box 14 and the moving tube member 13 through intermediate tube members 12 and 12". The gear boxes 14' and 14" are constructed entirely similarly to those shown either in FIGS. 20, 2b and 2c or in FIGS. 40 and 4b. Each of the intermediate tube member 12' or 12" has its one end fixedly connected to one gear box and its other end slidably connected to another gear box. If desired, the members 12 and/or 12" may be divided into two halves as already discussed with reference to FIGS. 3a and 3b. The modified guide tube thus constructed will provide an easier and more precise access to an affected part of a patient or an object to be scanned by the laser beam.

If desired, furthermore, the moving tube member 13 may also be divided into two halves 13a and 13b similarly to the stationary tube member 12 as best shown in FIGS. 3a and 3b. One half 13a is operatively connected at one end to the gear box 14 and slidably received at the other to the other half 13b. Also, a convex lens 37 may be provided in the half 13b of the tube member 13 so as to have the outgoing beam focussed at a given point. In this instance, the half 13b may be tapered at its leading end to add to the intensity of the beam thus focussed.

It will now be apparent from the foregoing description that the combination and relative positions of the spur gears used in the gear mechanism as herein disclosed may be varied without departing from the concept of the present invention. Thus, it will be understood that the embodiments of the inventive concept illustrated herein is exemplary and not exaustive,

' and that the invention is not limited to such embodiments,

since modifications and variations thereof, some of which have been pointed out hereinabove, may be made without departing from the spirit and scope of the invention as claimed in the appended claims.

We claim:

I. In an articulated guide tube for guiding an input beam emitted unidirectionally from a beam source including a stationary tube member connected at one end with said beam source for guiding the input beam, a gear box containing therein a rotatable reflector mirror for reflecting the guided input beam and fixedly connected to the other end of said stationary tube member, and a moving tube member opened at one end to an object and rotatably connected at the other end with said gear box for further guiding the reflected input beam to the object, the improvement comprising a gear mechanism in said gear box and including: a reflector support having a recess formed therein for fixedly carrying said reflector mirror; a pivotal shaft integrally connected with said reflector support and located at a point at which the extention of the axis of said stationary tube member intersects that of said moving tube member; a first spur gear rotatably mounted on said pivotal shaft and fixedly connected to said stationary tube member; a second spur gear fixedly mounted on said pivotal shaft at a spacing from said first spur gear; a stationary shaft parallel to and spaced from said pivotal shaft; a third spur gear rotatably mounted on said stationary shaft and engaging with said first spur gear; and a fourth spur gear mounted on said stationary shaft integrally with said third spur gear and engaging with said second spur gear, the gear ratio of said first and third spur gears being 1 vs. 2 and the gear ratio of said fourth and second spur gears being 1 vs. 1, whereby said reflector mirror is rotated by an angle equal to one-half of an angle by which said moving tube member is rotated with respect to said stationary tube member so that the beam passing through said stationary tube member is guided by and projected from said moving tube member in the direction thereof.

2. A tube according to claim 1 further comprising at least one additional gear box similar to said gear box and at least one additional intermediate tube member fixedly connected at one end to one of said gear boxes and slidably connected at the other to another gear box.

3. A tube according to claim 1, wherein said moving tube member includes two halves which are axially slidably held in mating engagement with each other whereby said moving tube member rotates about and slides along the axis of said stationary tube member.

4. A tube according to claim 1, wherein the leading end portion of said moving tube member is tapered toward its extreme end and is provided therein with a convex lens for focussing the guided beam on the object.

5. An articulated tube member according to claim 1, wherein said stationary tube member includes two halves one of which has a reduced end and the other has a bore fitting with said reduced end, said two halves peripherally slidably held in mating engagement with each other, whereby said moving tube member rotates about the axis of said stationary tube member.

6. An articulated guide tube according to claim 5 further comprising at least two cylindrical ball bearings interposed between said two halves, whereby said moving tube member rotates about the axis of said stationary tube member.

7. An articulated guide tube according to claim 5 further comprising a cylindrical roller bearings interposed between said two halves, whereby said moving tube member rotates about and slides along the axis of said stationary tube member.

8. In an articulated guide tube for guiding an input beam emitted unidirectionally from a beam source including a stationary tube member connected at one end with said beam source for guiding the input beam, a gear box containing therein a rotatable reflector mirror for reflecting the guided input beam and fixedly connected to the other end of said stationary tube member, and a moving tube member opened at one end to an object and bidirectionally rotatably connected at the other end with said gear box for further guiding the reflected input beam to the object, the improvement comprising first and second gear mechanisms in said gear box for operatively supporting said reflector mirror, said first gear mechanism including: a reflector support accommodated in a square-shaped box; a pair of pivotal shafts extending from said square-shaped box and pivotally received at their one ends by a pair of parallel fiat walls of said gear box; a pair of first spur gears rotatably mounted on said pivotal shafts and fixedly connected to said stationary tube member; a pair of s second spur gears fxedly mounted on said pivotal shafts at a spacing from said first spur gears; a pair of stationary shafts parallel to and spaced from said pivotal shafts; a pair of third spur gears rotatably mounted on said stationary shafts and engaging with said first spur gears, and a pair of fourth spur gears mounted on said stationary shafts integrally with said third spur gears, the gear ratio of said first and third spur gears being 1 vs. 2 and the gear ratio of said fourth and second spur gears being 1 vs. 1, and said second gear mechanism including: a pair of pivotal shafts inserted pivotally through the facing walls of said square-shaped box and fixedly connected to the outer walls of said reflector support; a pair of first spur gears rotatably mounted on said pivotal shafts of said second gear mechanism and fixedly connected to said stationary tube member; a pair of second spur gears fixedly mounted on said pivotal shafts of said second gear mechanism at a spacing from said first spur gears of said second gear mechanism; a pair of stationary shafts parallel to and spaced from said pivotal shafts of said second gear mechanism and fixedly connected to said squareshaped box; a pair of third spur gears rotatably mounted on said stationary shafts of said second gear mechanism and engaging with said first spur gears of said second gear mechanism; and a pair of fourth spur gears mounted on said stationary shafts of said second gear mechanism integrally with said third spur gears of said second gear mechanism, the gear ratio of said first and third spur gears of said second gear mechanism being 1 vs. 2; and the gear ratio of said fourth and second spur gears of said second gear mechanism being 1 vs. I, and said pairs of pivotal shafts of said first and second gear mechanisms being perpendicular to each other, whereby said reflector mirror is rotated by an angle equal to one-half both of an angle, by which said moving tube member is rotated with respect to said stationary tube member, and of an angle perpendicular to the second-mentioned angle so that the beam passing through said stationary tube member is guided by and projected from said moving tube member in the direction thereof.

9. A tube according to claim 8, wherein said first spur gears of said first and second gear mechanisms are fixedly connected to said moving tube member through four leaf springs angled at to one another.

It i i i 1 

1. In an articulated guide tube for guiding an input beam emitted unidirectionally from a beam source including a stationary tube member connected at one end with said beam source for guiding the input beam, a gear box containing therein a rotatable reflector mirror for reflecting the guided input beam and fixedly connected to the other end of said stationary tube member, and a moving tube member opened at one end to an object and rotatably connected at the other end with said gear box for further guiding the reflected input beam to the object, the improvement comprising a gear mechanism in said gear box and including: a reflector support having a recess formed therein for fixedly carrying said reflector mirror; a pivotal shaft integrally connected with said reflector support and located at a point at which the extention of the axis of said stationary tube member intersects that of said moving tube member; a first spur gear rotatably mounted on said pivotal shaft and fixedly connected to said stationary tube member; a second spur gear fixedly mounted on said pivotal shaft at a spacing from said first spur gear; a stationary shaft parallel to and spaced from said pivotal shaft; a third spur gear rotatably mounted on said stationary shaft and engaging with said first spur gear; and a fourth spur gear mounted on said stationary shaft integrally with said third spur gear and engaging with said second spur gear, the gear ratio of said first and third spur gears being 1 vs. 2 and the gear ratio of said fourth and second spur gears being 1 vs. 1, whereby saiD reflector mirror is rotated by an angle equal to one-half of an angle by which said moving tube member is rotated with respect to said stationary tube member so that the beam passing through said stationary tube member is guided by and projected from said moving tube member in the direction thereof.
 2. A tube according to claim 1 further comprising at least one additional gear box similar to said gear box and at least one additional intermediate tube member fixedly connected at one end to one of said gear boxes and slidably connected at the other to another gear box.
 3. A tube according to claim 1, wherein said moving tube member includes two halves which are axially slidably held in mating engagement with each other whereby said moving tube member rotates about and slides along the axis of said stationary tube member.
 4. A tube according to claim 1, wherein the leading end portion of said moving tube member is tapered toward its extreme end and is provided therein with a convex lens for focussing the guided beam on the object.
 5. An articulated tube member according to claim 1, wherein said stationary tube member includes two halves one of which has a reduced end and the other has a bore fitting with said reduced end, said two halves peripherally slidably held in mating engagement with each other, whereby said moving tube member rotates about the axis of said stationary tube member.
 6. An articulated guide tube according to claim 5 further comprising at least two cylindrical ball bearings interposed between said two halves, whereby said moving tube member rotates about the axis of said stationary tube member.
 7. An articulated guide tube according to claim 5 further comprising a cylindrical roller bearings interposed between said two halves, whereby said moving tube member rotates about and slides along the axis of said stationary tube member.
 8. In an articulated guide tube for guiding an input beam emitted unidirectionally from a beam source including a stationary tube member connected at one end with said beam source for guiding the input beam, a gear box containing therein a rotatable reflector mirror for reflecting the guided input beam and fixedly connected to the other end of said stationary tube member, and a moving tube member opened at one end to an object and bidirectionally rotatably connected at the other end with said gear box for further guiding the reflected input beam to the object, the improvement comprising first and second gear mechanisms in said gear box for operatively supporting said reflector mirror, said first gear mechanism including: a reflector support accommodated in a square-shaped box; a pair of pivotal shafts extending from said square-shaped box and pivotally received at their one ends by a pair of parallel flat walls of said gear box; a pair of first spur gears rotatably mounted on said pivotal shafts and fixedly connected to said stationary tube member; a pair of s second spur gears fixedly mounted on said pivotal shafts at a spacing from said first spur gears; a pair of stationary shafts parallel to and spaced from said pivotal shafts; a pair of third spur gears rotatably mounted on said stationary shafts and engaging with said first spur gears, and a pair of fourth spur gears mounted on said stationary shafts integrally with said third spur gears, the gear ratio of said first and third spur gears being 1 vs. 2 and the gear ratio of said fourth and second spur gears being 1 vs. 1, and said second gear mechanism including: a pair of pivotal shafts inserted pivotally through the facing walls of said square-shaped box and fixedly connected to the outer walls of said reflector support; a pair of first spur gears rotatably mounted on said pivotal shafts of said second gear mechanism and fixedly connected to said stationary tube member; a pair of second spur gears fixedly mounted on said pivotal shafts of said second gear mechanism at a spacing from said first spur gears of said second gear mechanism; a pAir of stationary shafts parallel to and spaced from said pivotal shafts of said second gear mechanism and fixedly connected to said square-shaped box; a pair of third spur gears rotatably mounted on said stationary shafts of said second gear mechanism and engaging with said first spur gears of said second gear mechanism; and a pair of fourth spur gears mounted on said stationary shafts of said second gear mechanism integrally with said third spur gears of said second gear mechanism, the gear ratio of said first and third spur gears of said second gear mechanism being 1 vs. 2; and the gear ratio of said fourth and second spur gears of said second gear mechanism being 1 vs. 1, and said pairs of pivotal shafts of said first and second gear mechanisms being perpendicular to each other, whereby said reflector mirror is rotated by an angle equal to one-half both of an angle, by which said moving tube member is rotated with respect to said stationary tube member, and of an angle perpendicular to the second-mentioned angle so that the beam passing through said stationary tube member is guided by and projected from said moving tube member in the direction thereof.
 9. A tube according to claim 8, wherein said first spur gears of said first and second gear mechanisms are fixedly connected to said moving tube member through four leaf springs angled at 90* to one another. 